Piston ring



May 7, L. A MEAD PI STON RING Filed April l5, 1927 INVENTOR im Mw *mw Bm? mw ATTORNEY Patented May 7, 1929.

LOUIS ANDREW MEAD, F BELIANCE, SOUTH DAKOTA.

PISTON RING.

Application led April 15,

This invention relates to the piston rings used in engines, and, while the following description'will be more particularly directed to the application of the rings to the pistons of internal combustion engines, it should be understood that the invention is equally valuable to all engines of the reciprocatin type regardless of the nature ofthe motive uid.

'One object of the .invention is to prevent leakage of the motive fluid past the pistons of such engines, with its consequent loss of power, and, in the case of internal combustion engines, the pumping of oil and loss of cornpression.

Another very important object ofthe invention is to provide a ring construction which will automatically compensate for the wear loccurring between the cylinders and piston rings of engines, and which will ensure an effective relationship of the said parts regardless of long and continuous operation of the engines.

Still another object of the invention is to provide a construction which Will automatically minimize the bad effects of faulty piston ring fitting.

With these and certain other objects in view, which will appear as the description proceeds, the invention resides in the novel construction, combination and arrangement of parts hereinafter first fully described in the following specification and later more particularly pointed out in th'e appended claims, reference also being had to the drawings forming part hereof in which similar characters of reference indicate similar parts throughout the different views, and. in which Fig. 'l is a side elevation of a piston and ring in which is embodied the invention, a portion of the ring being broken away to show the rib or flange on the piston which the ring is formed to fit.

Fig. 2 isa fragmentary sectional view through the piston and ring taken substantially upon the planeof the line 2--2 in Fig. 3 is a fragment of the head end of the piston apart from the ring which is shaped to cooperate therewith.

Fig. 4 is a side elevation 'of the piston ring having a portion broken away to show the interior thereof shaped to fit the piston.

In the drawings 5 indicates a piston of the type common to internal combustion en 'nes, the same being formed with a head 6, a ody 1927. Serial No. 184,003.

portion or skirt 7 and a hollow interior in which is accommodated a Wrist pin 8 sup. ported by bosses 9 on each side.

In the present disclosure the head end of the piston is reduced in diameter to provide the aligned lands 10 and 11, the said lands being separated by a rib or ridge 12 of less diameter than the skirt portion 7, having a downwardly bevelled or inclined face 13 and a peripheral face 14 in parallel with the faces otl the lands 10 and 11, the under side 15 of the rib being cut'at right angles to the face 14 ofthe same as is also the top 16 of the skirt 7 of the piston, thus forming a rectangular groove 17 around the piston below the rib 12 for a purpose now to be described.

piston ring 18 is interiorly shaped to have an upper portion 19 in cross section substantially equal to that of the land 10 upon which it is normally seated, a portion 20 adapted to be received in the groove 17, and a groove 21 having an inclined face 22 constantly in sliding contact with the bevelled face 13 on the rib 12, the said' groove 21 bein otlherwise shaped to receive and fit the said ri 12.

The ring 18 is preferably formed with a step cut joint 23 allowing it to expand under pressure as hereinafter explained and also allowing it to be sprung sufficiently to be placed in operative position on the piston 5 as is shown in Figs. 1 and 2. Inthis position it will be noted, that while the top and inner edge of the portion 20 of the ring 18 are normally in contactv with theuppe inner walls of the groove 17, which they adjoin, the said portion 20 of the ring does not completely fill the groove 17, but a s ace24 is left between the under side 25 of t e ring and the top 26 of the skirt of the piston.

The ring 18 may be formed from the usually resilient material common to such and the upper edge to the face thereof so as to resent a flat surface to the motive fluid in t el cylinder.

In the case of internal combustion engines but one rin is required upon the iston, that is to say, te ring 18 just descri steam engineering, owing to the fact that both ends of the piston are subject to pressure from the motive fluid, a posite end of the piston also, the parts of the second ring and piston being however reversed to meet and function from the opposite direction. 1

In Fig. 1, a second ring 28 isindicated in r andv devices, 27 stands at right angles ed, but in ring lis required on the opgainstpresure' 110 dotted lines upon the end 'of the piston most distant from the ring 18, the dottedlines 29 showing the reversed bevelling of the rib 12 required to adapt the ring 28 to meet and function against pressure rom the opposite direction, both rings adapting the piston to the requirements of steam engineering.

It is desirable that the tread line 3() of the step cut joint 23 should come just below the rib 12\to ensure the strength of the parts of the said joint.

With the ordinary type of piston rings the elasticity of the rings 1s depended upon to maintain an operative contact of the ring with the inner 'surface of the cylinder to prevent.

leakage of the motive fluid past the piston, but, as is well known particularly to motorists, leakage does occur. At times this leakage may be due to faulty fitting of the piston ring in the iirst place, possibly by the insertion of a ring of too small diameter yfor the cylinder in which it is expected to work; again, it may be due to loss of elasticity in the ring; and still again it may be due to the wear upon cylinder and ring resulting from long continued operation of the engine and for which the elasticity of the ring refuses to compensate. The present construction is calculated to overcome any or all of these troubles. y.

In gas engineering, during the compression as well as the explosive stroke, a ve considerable pressure is present in the cy inder, and, with a ring of the type disclosed herein, this pressure is exerted against the piston head 6 and the edge 27 of the ring 18 equally in proportion to the areas thereof. In operation the pressure in the cylinder operates upon'the edge 27 of the ring 18. to induce an axial displacement of the said ring upon the piston the bevelled face 13 on the riby 12 on the piston cooperating with the bevelled face 22 of the groove 21 1n the ring to expand the said ring out against the wall of the cylinder, this movement being indicated by the dotted lines 31 in Fig. 2 and the space 24 below the ring permitting of the same.

It will here be observed, that as a natural consequence of the reciprocation of the piston in the cylinder, loil will accumulate 1n the space 24 inthe groove 17 below the portion 20 of the rin 18, and that as the said ring is expanded 1n the manner described, down and out in the'diretion of the dotted lines 31 in Fig. 2, the lower portion of the said ring will be removed from contact with the upper and inner faces or walls of the groove 17 on the iston thus permitting oil to pass u freely om t e space 24 between the ring an piston to a position enabling it to penetrate between the inclined faces 13 and 22 on the piston and ring respectively, to lubricate and prevent the same from heatinng. As the cylinder w l and piston ring wear to each other through continued usage the effectiveness of the construction becomes more pronounced, the liability of leakage decreases i and shape to provide a land, a rib adjoining the land and a groove below the land; a ring having its upper. edge normally disposed in the plane of the head mounted upon the piston and `interiorly shaped to provide a portion to fit the land, a portion to receive the rib, and a lower portion disposed in the groove below the rib normally contacting the upper andinner walls of the said groove and spaced from the bottom thereof, and slidingly contacting bevelled faces on the' rib and ring cooperative to expand the said ring downwardly and outwardly upon axial displacement of the same upon the piston.

2. A piston comprising a head and a skirt having its upper end reduced in diameter and sha ed to provide a vertical land adj oining the ead, a rib below the land and a rectangular groove below the rib a ring mounted upon the piston having its upper edge normally lyin in the plane of the head interiorly shaped to t the land and receive the rib and having a lower portion disposed in the groove below the rib normally in contact with the 'upper and inner walls of the said groove and spaced from the bottom thereof, and slidingly contacting bevelled faces on the rib and ring cooperative to expand said rin downwardly and outwardly yupon axial isplacement of the same upon the piston.

'3. A l,iston comprising a head and skirt having its upper end shaped to provide a peripheral ri of less diameter than that of the skirt and a vgroove below the rib; a. ring mounted u on the piston having its u per edge norm ly lying in the plane of the ead of the. iston interi'orl shaped to receive the rib an to provide a. ower' portion disposed in the groove below the rib normally contacting the upper and inner walls of the said groove and spaced from the bottom'thereof to afford a recess in which oil may accumulate, and contacting bevelled faces on the rib and ring cooperative to expand the said ring downwardly and outwardly upon axial displacement of the same upon the iston to rethe walls of the groove.

contact with the lower portion of the saldring from' las 

